Qt 6

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I have never bumped into an error like that. Probably there is something wrong in how this QAIM is instantiated and d is either stale or nullptr.

Have you solved this problem yet? I'm having the same problem trying QT6!

@jsulm I understand now，thank you

@FeRDNYC said in Qcache a buggy class?:

...Or I suppose the docs could have a general explainer page about object ownership and lifetimes, which statements like the one quoted above are linked to. Devs moving from garbage-collected languages, in particular, don't necessarily have that background.

Qt is a library, and as @Christian-Ehrlicher mentioned, it's not any library's concern to teach you the underlying language - it is assumed that you're going to be using the library after you understand the basis of its existence.

I can see how if you are coming from a garbage-collected language this may sound unfair, but if you think about it for a while I think you'd agree that C++ is too large and too complex for you to require from Qt (developers) to feed you information about the language too.

Note: I'm liberally using "you", but do consider it as using the indefinite pronoun form.

@jsulm Hello, I found that I need to use oc and qt for mixed compilation, but I can't add the Foundation framework in cmake. How should I add it?

I checked the information and he said that iOS can only read and write at the location "QStandardPaths::standardLocations(QStandardPaths::DocumentsLocation).last()"

@jsulm ok thank you for the help. Indeed grateful.

@cristian-adam
Thanks Cristian!
I'll check this out.... ✌️

@Ash-V
Hi,
index is set to -5, model is set to {}, which means it's an empty, default constructed model.
Regardless if overridden or not, modelneither has a name, nor a typeproperty.
So I don't quite see the problem here.
Which value would you expect the properties to have?

@Dilabun
I had not looked closely at your code, but what @Ketan__Patel__0011 has written is certainly correct. If that is really the code you have been trying you have created two quite separate QAudioOutputs. The one in audioOutput whose volume you set is not the one which is player's output. So start by sorting that out!

@marisol Looks like gradle version mismatch. Read the links in my post above carefully and try to use the right versions for all packages.

You can try to install new version of Strawberry Perl. Perl is used to generate qmimeprovider_database.cpp as indicated by file "qtbase\src\corelib\mimetypes\mimetypes.pri".

mimedb.depends = $$PWD/mime/generate.pl equals(MAKEFILE_GENERATOR, MSVC.NET)|equals(MAKEFILE_GENERATOR, MSBUILD)|isEmpty(QMAKE_SH) { mimedb.commands = cmd /c $$shell_path($$PWD/mime/generate.bat) mimedb.depends += $$PWD/mime/generate.bat $$PWD/mime/hexdump.ps1 } else { mimedb.commands = perl $${mimedb.depends} }

Refer to https://www.qtcentre.org/threads/71253-Static-Build-Issue-on-QT-5-15-0?p=309507#post309507

Then, if "qmimeprovider_database.cpp" is generated correctly, the compilation works.

@Dragoner said in qtpropertybrowser with Qt6:

-Wa,-mbig-obj

(This is ONE compiler flag, so the comma is not a typo!)

Correct. Specifically, it says that the compiler should pass the comma-separated list of arguments that follows (-mbig-obj) to the assembler (-Wa), when it gets run.

There are also -Wp, flags, to pass arguments to the preprocessor stage, and -Wl, flags, when an option needs to go to the linker.

In gcc , at least, the -Xassembler, -Xpreprocessor, and -Xlinker flags can be used to do the same thing one argument at a time, without comma-separating them.

(e.g. these are equivalent:)

$ gcc -Xassembler -mbig-obj ... $ gcc -Wa,-mbig-obj ...

Hi and welcome to devnet,

AFAIK, you can't.

@cristian-adam After spending 6 hours trying to set up OpenCV with Qt6 while following several tutorials (only to find out that it all does not apply to Qt6), your solution worked perfectly fine.

I should only add that I struggled with Qt Creator GUI looking for cmake project settings to change CMAKE_PREFIX_PATH. but finally got it (CTRL+5) ,
Just bookmarked this thread for good.

many thanks for this!

@Ash-V Under Linux never type a capital/upper-case letter unless you have a very good reason for doing so.

@JonB

That fixed it! Thanks Christian and Jon for your help.

Sorry to be such a pain Christian.

Rick

This lead to QTBUG-123768